# Indices and Logarithms Help

• December 4th 2008, 12:30 PM
Ian360
Indices and Logarithms Help
hopefully can help explain these, they the last question i need to do but its mainly the reason i need
A) 2x-2 Equivalent expression 2/X-2
1/2x2 Equivalent expression ½ x -2
my problem is the reasoning for these

B) Log2(8) = 4 False My Answer - Log2(16) = 4
Log16(4)= 1/4 False My Answer - Log16(2) = 1/4
Log2(1/8)= -3 True

and again here its the reasoning but for my answers

i hope u can understand that :) i get it but for the reasoning i just go blank :S
• December 4th 2008, 01:40 PM
masters
Quote:

Originally Posted by Ian360
hopefully can help explain these, they the last question i need to do but its mainly the reason i need
A) 2x-2 Equivalent expression 2/X-2
1/2x2 Equivalent expression ½ x -2
my problem is the reasoning for these

B) Log2(8) = 4 False My Answer - Log2(16) = 4
Log16(4)= 1/4 False My Answer - Log16(2) = 1/4
Log2(1/8)= -3 True

and again here its the reasoning but for my answers

i hope u can understand that :) i get it but for the reasoning i just go blank :S

I don't see any reason for (A).

The reasoning for (B) is this:

$\log_ax=n$ means $a^n=x$
• December 4th 2008, 02:20 PM
Ian360
Quote:

Originally Posted by masters
I don't see any reason for (A).

The reasoning for (B) is this:

$\log_ax=n$ means $a^n=x$

thanks for the help on (B) cant believe how simple it is now for them

but now im stuck on the indices how can you tell if they are similar and which give products of 1..2...3 etc etc
http://i490.photobucket.com/albums/r...3/RIMG0009.jpg this is what im having to do i need to match 2 with the equivant equation and also match 2 that give a product of 1...this is confusing me as in my notebook its tell me that indices are a3 + d2 something like that
• December 5th 2008, 06:21 AM
masters
(Nod)
Quote:

Originally Posted by Ian360
thanks for the help on (B) cant believe how simple it is now for them

but now im stuck on the indices how can you tell if they are similar and which give products of 1..2...3 etc etc
http://i490.photobucket.com/albums/r...3/RIMG0009.jpg this is what im having to do i need to match 2 with the equivant equation and also match 2 that give a product of 1...this is confusing me as in my notebook its tell me that indices are a3 + d2 something like that

I'm still not sure exactly what you're trying to do, but as far as finding products that equal 1, 2, etc.

Rewriting the rows:

$\frac{1}{2x^2} \ \ \ \ \frac{1}{2\sqrt{x}} \ \ \ \ \frac{2}{x} \ \ \ \ \frac{2}{\sqrt{x}} \ \ \ \ \frac{1}{2x}$

$2\sqrt{x} \ \ \ \ \frac{2}{x^2} \ \ \ \ \frac{1}{2\sqrt{x}} \ \ \ \ \frac{1}{2x^2} \ \ \ \ 2x^2$
----------------------------------------------------------------------
$\frac{1}{2x^2}\cdot 2x^2 = 1$

$2\sqrt{x} \cdot \frac{1}{2\sqrt{x}}=1$

$\frac{2}{x^2}\cdot 2x^2=4$

Is this what you're talking about? If so, try some products and see what happens.
• December 5th 2008, 06:32 AM
Ian360
Quote:

Originally Posted by masters
(Nod)

I'm still not sure exactly what you're trying to do, but as far as finding products that equal 1, 2, etc.

Rewriting the rows:

$\frac{1}{2x^2} \ \ \ \ \frac{1}{2\sqrt{x}} \ \ \ \ \frac{2}{x} \ \ \ \ \frac{2}{\sqrt{x}} \ \ \ \ \frac{1}{2x}$

$2\sqrt{x} \ \ \ \ \frac{2}{x^2} \ \ \ \ \frac{1}{2\sqrt{x}} \ \ \ \ \frac{1}{2x^2} \ \ \ \ 2x^2$
----------------------------------------------------------------------
$\frac{1}{2x^2}\cdot 2x^2 = 1$

$2\sqrt{x} \cdot \frac{1}{2\sqrt{x}}=1$

$\frac{2}{x^2}\cdot 2x^2=4$

Is this what you're talking about? If so, try some products and see what happens.

thats what i was talking about thanks for the help i understand how it works now